1. Field of the Invention
The present invention relates to a foreign matter removing structure, which can be applied to refrigerant circulating circuits (refrigeration cycles) for systems such as air conditioning systems, etc., and is used for removing foreign matter in a refrigerant gas flowing through the refrigerant circulating circuits.
2. Description of the Related Art
As this kind of foreign matter removing structure, for example, Japanese Unexamined Patent Publication (Kokai) No. 6-235569 discloses that a filter is disposed in a refrigerant passage.
However, in the art in the prior publication described above, a simple construction in which the filter is arranged so as to disturb the refrigerant flow is used. Therefore, if blockage of the element of the filter occurs, the refrigerant flow is unnecessarily reduced in the element, resulting in deterioration of the efficiency of the refrigeration cycle and a decrease of the capacity of the air conditioning system.
The purpose of the present invention is to provide a foreign matter removing structure, which maintains its removing function for foreign matter even if blockage of a filter element occurs and which disturbs a fluid flow as little as possible.
To realize the above-mentioned purpose, the first aspect of the present invention provides a foreign matter removing structure characterized in that it includes a filter which can remove foreign matter in a fluid flowing through a fluid circuit wherein the filter comprises; a cylindrical filter body which is disposed in a fluid passage of the fluid circuit, a lid portion installed so as to close an opening positioned downstream of the fluid passage in the filter body, communication holes which penetrate through the filter body and communicate the inside of the filter body with the outside thereof, and one or a plurality of filter elements which are disposed in the filter body and/or the lid portion so as to be positioned more downstream than the communication holes; wherein a gap between an outer circumferential surface of the filter body and an inner circumferential surface of the fluid passage is closed at the upstream side of the communication holes.
In the above construction, a fluid flowing into the fluid passage then flows into the filter body through an opening in an upstream side. A part of the fluid flowing into the filter body is discharged to the outside of the filter body while foreign matter is removed by the filter elements.
Also, a part of the fluid flowing into the filter body is discharged to the outside of the filter body through the communication holes. The fluid discharged to the outside of the filter body flows through a space between the outer circumferential surface of the filter body and the inner circumferential surface of the fluid passage to be discharged to the downstream side of the filter. The flow direction of the fluid passing through this flow route is sharply changed when it is discharged out of the filter body. As a result, the foreign matter in the fluid are centrifugally separated from the fluid when the fluid flow direction is sharply changed.
On the other hand, if a blockage occurs in the filter elements, it becomes difficult for the fluid in the filter body to flow through the filter elements and to be discharged from the filter body. However, other than a first route in which a fluid flows through the filter elements and is discharged, a second discharging route including the communication holes therein is provided as a route for discharging the fluid out of the filter body. Therefore, even if a blockage occurs in the filter elements, that is, in the first route, the second route allows the fluid to pass therethrough, so that the function of removing foreign matter can be maintained and at the same time it can be prevented, as much as possible, that the fluid flow is disturbed by the filter.
The second aspect of the present invention according to the first aspect thereof is characterized in that the filter elements are disposed in the filter body and the lid portion.
In this construction, the filter elements have a three dimensional arrangement as a whole, so that the filtering of the fluid by the element is accomplished widely on the surfaces provided in the three dimensional arrangement and the foreign matter removing capacity (the capacity preventing foreign matter from passing downstream) of the present structure is improved.
The third aspect of the present invention according to either of the first or the second aspect thereof is characterized in that, in the fluid passage, a foreign matter holding recess is formed below the communication holes.
In this construction, foreign matter separated in the second route is surely held in the foreign matter holding recess, so that the foreign matter removing capacity of the present structure is improved.
The fourth aspect of the present invention provides a foreign matter removing structure characterized in that it includes a filter which can remove foreign matter in a fluid flowing through a fluid circuit wherein the filter comprises; a cylindrical filter body which is disposed in a fluid passage of the fluid circuit, a lid portion installed so as to close an opening positioned upstream of the fluid passage in the filter body, communication holes which penetrate through the filter body and communicate the inside of the filter body with the outside thereof, and one or a plurality of filter elements which are disposed in the filter body so as to be positioned downstream of the communication holes; wherein a gap between an outer circumferential surface of the filter body and an inner circumferential surface of the fluid passage is closed downstream of the filter elements.
In the above construction, a fluid flowing into the fluid passage is then forced to flow through at the side of the lid portion by the lid portion opposing the fluid flow. A part of the fluid flowing through the side of the lid portion flows through a space between the outer circumferential surface of the filter body and the inner circumferential surface of the fluid passage to flow into the inside of the filter body, while foreign matter is removed by the filter elements. The fluid, flowing into the inside of the filter body after foreign matter is removed, is discharged out of the filter body through a hole on the downstream side.
The flow direction of a part of the fluid flowing through the side of the lid portion in the fluid passage is sharply changed and the fluid is turned around the outer circumferential edge of the lid portion and part of the fluid flows into the filter body through the communication holes. As a result, the foreign matter in the fluid is centrifugally separated from the fluid by the sharp change of the fluid flow direction and the foreign matter falls into a space between the outer circumferential surface of the filter body and the inner circumferential surface of the fluid passage, that is, inside the foreign matter holding recess positioned in the area lower than the communication holes, and is held in the space. The fluid, which flows into the filter body and from which the foreign matter is removed, is discharged out of the filter body through a hole located downstream.
In this aspect of the present invention, as in the first aspect thereof described above, other than the first route in which the fluid flows through the filter elements and is discharged, a second route, including the communication holes through which the fluid passes, is provided. Therefore, even if blockage of the filter elements, that is, in the first route, occurs, the second route allows the fluid to pass therethrough, so that the function of removing foreign matter can be maintained and at the same time it can be prevented, as much as possible, that the fluid flow is disturbed by the filter.
The fifth aspect of the present invention according to the fourth aspect thereof is characterized in that the filter element is also disposed in the lid portion.
In this construction, a new fluid passage, in which a fluid passes through the filter element in the lid portion into the filter body, is formed. Therefore, the foreign matter removing capacity of the present structure is improved.
The sixth aspect of the present invention, according to either of the fourth or the fifth aspect thereof, is characterized in that, on the outer circumferential surface of the filter body, a convex portion is provided upstream of the communication holes.
In this construction, due to the convex portion, the effect of sharp change of the fluid flowing direction in which the fluid flows into the communication holes through the side of the lid portion is enhanced and the centrifugal separation of the foreign matter is effectively accomplished.
The seventh aspect of the present invention according to the sixth aspect thereof is characterized in that the outer circumferential surface of the convex portion is formed in a tapered shape which has a smaller diameter on the communication holes side.
In this construction, due to the outer circumferential surface, of the convex portion, being formed in a tapered shape, the fluid is guided to flow into the communication holes, so that the effect of sharp change of the fluid flowing direction, by the convex portion, is more effectively realized.
The eighth aspect of the present invention according to any one of the fourth to the seventh aspects thereof is characterized in that the outer end surface of the lid portion is formed in a cone shape which opposes the fluid flow.
In this construction, the effect of sharp change of the fluid flowing direction at the outer circumferential edge of the lid portion is enhanced more than in the case in which the outer end surface of the lid portion is formed as a flat plane, for example.
The ninth aspect of the present invention is a compressor characterized in comprising the foreign matter removing structure, according to any one of the first to the eighth aspects of the present invention, in a gas passage in the inside of the housing.
In this construction, even if blockage occurs in the filter elements, the function of removing foreign matter can be maintained and at the same time it can be prevented, as much as possible, that the gas flow passing through the filter is disturbed.
The compressor according to the ninth and the tenth aspects of the present invention is a variable displacement type and the gas passage is used for the displacement control of the compressor.
The present invention may be more fully understood from the description of the preferred embodiments of the invention, as set forth below, together with the accompanying drawings.